Drug & supplement interaction

Kava + Loncastuximab Tesirine-Lpyl

Loncastuximab Tesirine-Lpyl brand name: Zynlontab.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Kava has a moderate interaction with Loncastuximab Tesirine-Lpyl. It is unclear if kava inhibits P-glycoprotein (P-gp); research is conflicting.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Kava and Loncastuximab Tesirine-Lpyl

Here is the interaction we found between these two, with the evidence behind it.

Moderate

P-GLYCOPROTEIN SUBSTRATES

Why this applies to Loncastuximab Tesirine-Lpyl

Loncastuximab Tesirine-Lpyl falls under P-GLYCOPROTEIN SUBSTRATES — the group Kava interacts with.

It is unclear if kava inhibits P-glycoprotein (P-gp); research is conflicting.
In vitro research shows that kava can inhibit P-gp efflux. However, a clinical study in healthy volunteers shows that taking kava standardized to provide 225 mg kavalactones daily for 14 days does not affect the pharmacokinetics of digoxin, a P-gp substrate. It is possible that the use of other P-gp substrates or higher doses of kava might still inhibit P-gp.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the honest picture with Zynlonta (loncastuximab tesirine) and kava. This concern is based on the idea that kava might block a cellular pump called P-glycoprotein, which can move certain drugs out of cells. In theory, blocking it could let more drug stick around. But the evidence here is weak and mixed. Test-tube studies hinted at this, yet a human study showed kava did not change levels of digoxin, another drug that relies on that same pump.

On top of that, Zynlonta is a powerful infused cancer therapy given by your oncology team, not something this supplement is likely to meaningfully shift. The bigger real concern is that both kava and this medication can stress the liver, so combining them isn't wise. Please don't start kava without first clearing it with your oncologist or pharmacist.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Weiss J, Sauer A, Frank A, Unger M. Extracts and kavalactones of Piper methysticum G. Forst (kava-kava) inhibit P-glycoprotein in vitro. Drug Metab Dispos 2005;33:1580-3. PubMed
  2. Gurley BJ, Swain A, Barone GW, et al. Effect of goldenseal (Hydrastis canadensis) and kava kava (Piper methysticum) supplementation on digoxin pharmacokinetics in humans. Drug Metab Dispos 2007;35:240-5. PubMed
  3. Asher GN, Corbett AH, Hawke RL. Common Herbal Dietary Supplement-Drug Interactions. Am Fam Physician. 2017;96(2):101-107.

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Kava Also Interacts With Other Medications

Kava has 248 major, 576 moderate, 341 minor known drug interactions in our database — the Loncastuximab Tesirine-Lpyl one above is one of them. If you take anything else, check it against the full list below.

Major 248 Moderate 576 Minor 341 No known interaction 1,665 (incl. Loncastuximab Tesirine-Lpyl)
Taking anything else?

Check Another of Your Medications Against Kava

Covers the 2,830 medications we’ve checked against Kava. Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Loncastuximab Tesirine-Lpyl

This page covers Kava only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Loncastuximab Tesirine-Lpyl page lists 37 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: St. John's Wort (major), Bitter Melon (moderate), Black Pepper (moderate), Bulbine Natalensis (moderate) and Cannabis (moderate).

By severity: 1 major · 28 moderate · 8 minor.

From our pharmacist’s overview on the Loncastuximab Tesirine-Lpyl page

“Loncastuximab tesirine (Zynlonta) is an infusion treatment for lymphoma that has come back or stopped responding, so I treat anything that can shift its levels as a real safety question. All 37 ingredients on file interact through the same doorway, a transporter called P-glycoprotein that moves drugs across cell membranes.”

Reviewed by 2 · Jul 18, 2026

Open the Loncastuximab Tesirine-Lpyl interaction page

One more smart check

Taking Kava as Part of a Dietary Supplement Product? Check It for Interactions

We hold 403 real supplement products containing Kava, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Kava. Your product may carry other ingredients that interact with Loncastuximab Tesirine-Lpyl too, on top of Kava — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Kava and Loncastuximab Tesirine-Lpyl Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Kava
Top 25%

#231 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Loncastuximab Tesirine-Lpyl
Top 25%

#526 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Supplement

About Kava

What is Kava?

Kava
  • Anxiety and stress
  • Restlessness
  • Trouble sleeping
  • Relaxation in social or cultural settings
  • Menopausal symptoms

Kava is a Pacific Island plant traditionally used to promote relaxation and ease anxiety, and some studies suggest it may help mild anxiety. However, kava has been linked to rare but serious liver damage, so it should be used with caution, avoided by people with liver problems, and only used after talking with your pharmacist or doctor.

Read the full Kava monograph & all interactions
Medication

About Loncastuximab Tesirine-lpyl Injection

What Is Loncastuximab Tesirine-lpyl Injection Used For?

Brand name: Zynlontab

  • Loncastuximab tesirine-lpyl injection is used to treat a certain type of non-Hodgkin's lymphoma (NHL; a type of cancer that begins in a type of white blood cells that normally fights infection) that did not respond to or has returned after treatment with at least two other cancer treatments. Loncastuximab tesirine-lpyl is in a class of medications called antibody-drug conjugates. It works by killing cancer cells.

See full Loncastuximab Tesirine-lpyl Injection drug information
Keep checking

Other Drugs & Kava

Browse every other medication we’ve checked against Kava — both the ones with a known interaction and the ones without. Select any drug for the full detail.

248Major
576Moderate
341Minor
1,664No known interaction
248 Major 576 Moderate 341 Minor 1,664 No interaction
Major

248 interactions

Showing 60 of 248 major interactions — see all 248 on the Kava page.

Moderate

576 interactions

Showing 60 of 576 moderate interactions — see all 576 on the Kava page.

Minor

341 interactions

Showing 60 of 341 minor interactions — see all 341 on the Kava page.

No interaction 1,664 drugs checked — show the list

We also checked Kava against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 1,664 medications checked with no known interaction — see the full Kava list.

See the full Kava interactions page
See every supplement checked against Loncastuximab Tesirine-Lpyl, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Kava monograph › Uses, safety, and every drug interaction in one place Loncastuximab Tesirine-Lpyl supplement interactions › Every supplement checked against Loncastuximab Tesirine-Lpyl, ranked by severity Loncastuximab Tesirine-lpyl Injection drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Kava and Loncastuximab Tesirine-Lpyl Together: Common Questions

Can you take Kava with Loncastuximab Tesirine-Lpyl?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Kava and Loncastuximab Tesirine-Lpyl interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Loncastuximab Tesirine-Lpyl and Kava?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.